U.S. patent number 7,676,932 [Application Number 11/365,717] was granted by the patent office on 2010-03-16 for knife with spring-assisted blade articulation mechanism.
Invention is credited to Jerry L. Grice, Tycelia Grice, legal representative.
United States Patent |
7,676,932 |
Grice , et al. |
March 16, 2010 |
Knife with spring-assisted blade articulation mechanism
Abstract
A knife with a spring-assisted articulation mechanism for
assisting the user in the folding and unfolding of the blade from
the pocket of the liner. The spring-assisted articulation mechanism
also helps retain the blade in the folded position to prevent the
blade from becoming unintentionally unfolded. The knife includes a
pocketed liner and a blade attached to liner at one end of the
liner by a pivot pin. The blade has a pointed end and a base end,
the base end pivotally secured to the second end of the liner by
the pivot pin such that the blade is capable of pivoting between a
folded "closed" position and an unfolded "open" position. A guide
pin is also attached to the blade of the knife at the base. A
spring is provided to exert a closing force on the blade when the
blade is in the closed position and an opening force on the blade
when the user moves the blade into a partially open position.
Inventors: |
Grice; Jerry L. (Crawfordville,
FL), Grice, legal representative; Tycelia (Crawfordville,
FL) |
Family
ID: |
36651730 |
Appl.
No.: |
11/365,717 |
Filed: |
March 1, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20060150422 A1 |
Jul 13, 2006 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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10745793 |
Dec 29, 2003 |
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Current U.S.
Class: |
30/160; 30/159;
30/155; 30/153 |
Current CPC
Class: |
B26B
1/042 (20130101) |
Current International
Class: |
B26B
1/04 (20060101) |
Field of
Search: |
;30/153,155-161
;7/118,900 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nguyen; Phong H
Attorney, Agent or Firm: Horton; J. Wiley
Parent Case Text
CROSS-REFERENCES TO RELATED APPLICATIONS
This is a Continuation-in-part of U.S. patent application Ser. No.
10/745,793 filed Dec. 29, 2003, now abandoned and names the same
inventor.
Claims
Having described my invention, I claim:
1. A folding knife comprising: a. a liner having a first side, a
second side, an open top leading to a pocket, a bottom, a first
end, a second end, and a medial section therebetween; b. a blade
having a pointed end and a base end, said base end pivotally
secured to said second end of the liner such that said blade is
capable of pivoting between a closed position wherein said blade is
received within said pocket and an open position wherein said blade
pivots out of said pocket through said open top and extends
outwardly from said second end of the liner; c. a guide pin
projecting outward from said base end of said blade and through
said first side of said liner; d. a spring arm having a base, a
tip, a top surface facing in the direction of said open top of said
liner, and an apex in said top surface proximal said tip; said
spring arm secured to said liner by said base of said spring arm
and said tip extending toward said second end of said liner; said
spring arm positioned between said bottom of said pocket and said
guide pin on said blade; e. a blade lock having a first end, a
second end, a medial section therebetween, and a tongue proximal
said first end of said blade lock protruding towards said open top
of said liner; said blade lock secured to said liner proximal said
bottom of said liner by a pivot joint between said first end and
said second end of said blade lock; f. wherein said spring arm
supplies a closing force on said guide pin when said blade is in
said closed position, said closing force resisting the articulation
of said blade from said closed position to said open position; g.
wherein said spring arm supplies an opening force on said guide pin
after said blade passes a first equilibrium position during
articulation of said blade from said closed position to said open
position, said opening force assisting the articulation of said
blade from said first equilibrium position to said open position;
and h. wherein said blade lock exerts a resisting force opposing
articulation of said blade to a completely open position, such that
a second equilibrium position is achieved before said blade is
articulated to said completely open position.
2. The folding knife of claim 1, wherein during articulation of
said blade from said closed position to said open position, said
guide pin engages said spring arm between said tip and said apex
and upon articulation of said blade from said closed position to
said open position, said guide pin passes over said apex.
3. The folding knife of claim 1, said blade further comprising a
cam proximal said base end of said blade, said cam configured to
engage said tongue of said blade lock as said blade is articulated
from said closed position to said open position.
4. The folding knife of claim 3, said spring arm further comprising
a toe proximal said base of said spring arm, said toe configured to
provide resistive force against said second end of said blade lock
so that said tongue of said blade lock bears against said cam and
resists said opening force supplied by said spring arm.
5. The folding knife of claim 1, said spring arm further comprising
a toe proximal said base of said spring arm, said toe configured to
engage said second end of said blade lock rotates around said pivot
joint.
6. The folding knife of claim 1, said top surface of said spring
arm having a convex profile facing said open top of said liner at
said apex.
7. A folding knife having an assistive opening and closing
mechanism for assisting a user in opening and closing said folding
knife, said folding knife comprising: a. a liner having a first
side, a second side, an open top leading to a pocket, a bottom, a
first end, a second end, and a medial section therebetween; b. a
blade having a pointed end and a base end, said base end pivotally
secured to said second end of the liner such that said blade is
capable of pivoting between a closed position wherein said blade is
received within said pocket and an open position wherein said blade
pivots out of said pocket through said open top and extends
outwardly from said second end of the liner; c. a guide pin
projecting outward from said base end of said blade and through
said first side of said liner; d. a spring arm, said spring arm
secured to said liner and configured to engage said guide pin; e. a
blade lock having a first end, a second end, a medial section
therebetween; said blade lock secured to said liner proximal said
bottom of said liner; f. wherein during articulation of said blade
from said closed position to said open position said folding knife
passes through a plurality of stages including i. a closed stage,
wherein said spring arm exerts a closing force on said blade, said
closing force resisting articulation of said blade from said closed
position to said open position; ii. a partially open stage, wherein
said spring arm exerts an opening force on said blade, said opening
force assisting articulation of said blade from said closed
position to said open position; iii. a first equilibrium stage
occurring between said closed stage and said partially open stage
during articulation of said blade from said closed position to said
open position; wherein said spring arm exerts a neutral force; iv.
a second equilibrium stage occurring after said partially open
stage and before said blade is fully articulated to a completely
open stage; wherein said opening force exerted by said spring arm
is counteracted by a resistive force exerted on said blade by said
blade lock causing said blade to remain only partially open until
said user exerts an additional opening force on said folding
knife.
8. The folding knife of claim 7, said blade lock further comprising
a tongue proximal said first end of said blade lock protruding
towards said open top of said liner.
9. The folding knife of claim 8, said blade further comprising a
cam proximal said base end of said blade, said cam configured to
engage said tongue of said blade lock as said blade is articulated
from said closed position to said open position.
10. The folding knife of claim 9, said spring arm further
comprising a toe proximal said base of said spring arm, said toe
configured to provide resistive force against said second end of
said blade lock so that said tongue of said blade lock bears
against said cam and resists said opening force supplied by said
spring arm.
11. The folding knife of claim 7, said spring arm further
comprising a toe proximal said base of said spring arm, said toe
configured to engage said second end of said blade lock rotates
around said pivot joint.
12. The folding knife of claim 7, said spring arm having a top
surface facing said open top of said liner, said top surface having
a convex profile facing said open top of said liner.
Description
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
MICROFICHE APPENDIX
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field folding knives. More
specifically the present invention comprises a folding knife with a
mechanism for assisting the articulation of the blade in and out of
the pocket.
2. Description of the Related Art
Retractable knives, those knives that have blades that retract into
the liner of the particular knife, come in a variety of shapes and
sizes. Retractable knives fall into one of two broad categories.
Some knives feature a blade which is retracted into and extended
from its liner in a straight fashion. These knives are often
referred to as stilettos. Stilettos utilize a spring to eject the
blade from the liner when a button is pressed. Most jurisdictions
prohibit the sale and possession of these types of knives.
A second type of retractable knife is the folding variety. These
types of knives are commonly referred to as folding knives or
pocket knives. Folding knives have blade which is pivotally
connected to its liner at one end. The blade pivots between an
unfolded position where the blade is extended out from the liner
and a folded position where the blade rests within the pocket of
the liner. Many folding knives are manual in that folding and
unfolding of the blade is performed entirely by the user. Other
folding knives are spring assisted where a spring assists in
unfolding of the blade from the liner.
Spring assisted folding knives also come in different varieties. In
one variety, the blade is held under a constant spring force while
the blade is in the folded position within the pocket of the liner.
The blade is held in place by some form of lock, typically some
form of button. When the lock is released, the blade rapidly flips
to the extended position by the action of the spring. Such knives,
commonly called switchblades, are also illegal to sell and possess
in many jurisdictions.
Another type of spring assisted folding knives utilizes a spring to
assist in the unfolding operation after the user begins the
unfolding process manually. The spring starts to assist the user
once the user has partially unfolded the blade from the liner. The
combined forces of the user and the spring work to fully unfold the
blade into the open position.
While many different types of spring-assisted unfolding mechanisms
are known, much less attention has been given to features which
assist in the blade folding process. In addition, less attention
has been given to features which keep the blade in the folded
position. Such a feature requires some active force in order to
fully fold the blade into its pocket in order to prevent the blade
from accidentally unfolding in the user's pocket or onto the user's
fingers.
It is therefore desirable to provide a spring-assisted folding
mechanism that will assist the user in articulating the blade in
and out of the pocket. It would also be desirable to provide a
spring-assisted folding mechanism that helps retain the blade in
the pocket. By helping keep the blade in the fully folded position,
such systems help prevent the accidental partial unfolding of the
blade and the attendant possibility for injury that can result from
a blade being unexpectedly unfolded from its liner.
BRIEF SUMMARY OF THE INVENTION
The present invention comprises a knife with a spring-assisted
articulation mechanism for assisting the user in the folding and
unfolding of the blade from the pocket of the liner. The
spring-assisted articulation mechanism also helps retain the blade
in the folded position to prevent the blade from becoming
unintentionally unfolded. The knife includes a pocketed liner and a
blade attached to liner at one end of the liner by a pivot pin. The
blade has a pointed end and a base end, the base end pivotally
secured to the second end of the liner by the pivot pin such that
the blade is capable of pivoting between a folded "closed" position
and an unfolded "open" position. A guide pin is also attached to
the blade of the knife at the base.
A spring arm is attached the liner and is used to supply a spring
force to the guide pin. The spring arm is secured to the liner at
its base, and has a free-moving tip and an apex near the tip. A
cutout is provided in one side of the liner to permit movement of
the spring arm. An arcuate slot is also provided in the side of the
liner to permit the guide pin to project from the blade through the
liner and travel radially about the pivot screw when the blade is
articulated.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a perspective view, showing the present invention.
FIG. 2 is an exploded view, showing the present invention.
FIG. 3A is a perspective view, showing the present invention.
FIG. 3B is a detail view, showing the present invention.
FIG. 3C is a detail view, showing the present invention.
FIG. 4A is a detail view, showing the present invention.
FIG. 4B is a detail view, showing the present invention.
FIG. 5 is a detail view, showing the present invention.
FIG. 6 is a detail view, showing the present invention.
FIG. 7 is a detail view, showing the present invention.
REFERENCE NUMERALS IN THE DRAWINGS
TABLE-US-00001 10 folding knife 12 blade 14 liner 16 pocket 18
bolster 20 spring arm 22 apex 24 arm tip 26 pivot pin 28 guide pin
30 arm base 32 contact point 34 contact tangency line 36
contact-pivot line 38 arm cutout 40 arcuate slot 42 blade lock 44
pivot 46 lock base 48 lock tongue 50 blade cam 52 blade notch 54
spacer 56 spring arm slot 58 bore 60 toe
DETAILED DESCRIPTION OF THE INVENTION
The present invention, folding knife 10 is illustrated in FIG. 1.
Folding knife 10 includes blade 12 which articulates into and out
of pocket 16 of liner 14. Blade 12 is pivotally attached to one end
of liner 14 so that the cutting surface of blade 12 is contained
within liner 14 when folding knife 10 is in the closed position. In
the present illustration, folding knife 10 is shown in the
partially open position. Folding knife 10 includes a locking
mechanism which locks blade 12 in position when the user
articulates the blade to the completely open position. Bolsters 18
are sandwiched around both sides of liner 14. Bolsters 18
facilitate gripping and hide moving parts of folding knife 10 which
would otherwise be exposed through liner 14.
An exploded view of folding knife 10 is provided in FIG. 2. The
exploded view illustrates the various parts of folding knife 10.
Liner 14 is actually composed of three separate pieces--one
corresponding to each side of liner 14, and spacer 54 positioned
therebetween. When folding knife 10 is assembled spacer 54, blade
12, spring arm 20, and blade lock 42 are held in place by the side
pieces of liner 14. In the assembled state, the base of spring arm
20 is captured thin spring arm slot 20 in spacer 54. Blade lock 42
is held in position by a pin placed through pivot 44. Blade 12 is
held in position by pivot pin 26 which extends through both sides
of the liner and bore 58 provided near the base of blade 12.
Bolsters 18 are then attached around liner 14.
FIG. 3A shows folding knife 10 with blade 12 in the closed position
and bolsters 18 removed. Blade 12 includes guide pin 28 positioned
near the base of blade 12. Guide pin 28 is radially offset from
pivot pin 26 so that guide pin 28 travels in a substantially
circular path around pivot pin 26 when blade 12 is articulated.
Spring arm 20 extends outside of liner 14 through a cutout in liner
14 and is shaped so that spring arm 20 bears against guide pin 28
near the tip of spring arm 20.
As shown in FIG. 3B, spring arm 20 includes "U" shaped arm base 30
and apex 22 near arm tip 24. Apex 22 denotes the highest point
along the curved surface of spring arm 20 when blade 12 is in the
closed position in the perspective shown in the present view. The
reader will note that the two sides of arm base 30 are compressed
together slightly by when blade 12 is in the closed position.
Spring arm 20 extends through arm cutout 38 in liner 14. Arm cutout
38 allows spring arm 20 to travel up and down during articulation
of blade 12. Arcuate slot 40 is also provided in liner 14 so that
guide pin 28 can extend through the liner and travel in a
substantially circular path around pivot pin 26 during articulation
of blade 12.
As illustrated in by the arrow in FIG. 3C, spring arm 20 exerts a
spring force on guide pin 28 at contact point 32. When blade 12 is
in the closed position the spring force acts as a "closing force"
or "closing torque" that tends to keep the blade in the closed
position. Spring arm 20 has a curved surface facing guide pin 28.
At contact point 32, the spring force exerted by spring arm 20 is
normal to contact tangency line 34. Contact tangency line 32 is a
line tangent to the surface of spring arm 20 at contact point 32.
In order for spring arm 20 to provide a closing force when the
blade is in the closed position, guide pin 28 is positioned at a
location where spring arm 20 will interact with guide pin 28 in
such a way that the spring force will counteract the articulation
of the blade. Contact-pivot line 36 illustrates the relationship
between contact point 32 and the center of rotation or pivot pin
26. The component of the spring force acting perpendicular to
contact-pivot line 36 supplies the closing force.
FIG. 4A illustrates folding knife 10 with blade 12 in a partially
open position. In this perspective, the reader will observe that
blade lock 42 is in its normal position. Lock base 46 is positioned
under arm base 30. Lock tongue 48 protrudes from blade lock 42 in
the direction of the base of blade 12. When the blade is at this
stage of articulation, lock tongue 48 is positioned near the base
of blade 12 but is not actually touching the blade.
FIG. 4B is a detailed view of folding knife 10 in the stage of
articulation shown in FIG. 4A. The reader will note that guide pin
28 has traveled a small distance across the surface of spring arm
20 so that the contact point between guide pin 28 and spring arm 20
is near apex 22. At this stage of articulation contact tangency
line 34 is perpendicular to contact-pivot line 36. As before, the
arrow illustrates the spring force exerted by spring arm 20 on
guide pin 28. At this stage of articulation, folding knife 10 has
reached a balance or equilibrium point. Because the spring force is
in the direction of contact-pivot line 36, there is no component of
the spring force acting perpendicular to contact-pivot line 36.
Accordingly, spring arm 20 exerts a neutral force since there is
neither any closing force nor any opening force at this stage.
FIG. 5 shows folding knife 10 when blade 12 is articulated past the
equilibrium point shown in FIGS. 4A and 4B. Guide pin 28 has
traveled further along the surface of spring arm 20 so that it
passes over apex 22. Contact tangency line 34 and contact-pivot
line 36 are also illustrated. The reader will note that the spring
force (force exerted by the spring perpendicular to contact
tangency line 34) supplies an opening force on blade 12 when
folding knife 10 is in the present stage of articulation. Like the
closing force, opening force is proportional to the component of
the spring force acting perpendicular to contact-pivot line 36.
Blade cam 50 is provided at the base of blade 12. Because blade cam
50 has an increasing radius, blade cam 50 approaches lock tongue 48
as blade 12 is articulated and blade cam 50 rotates around pivot
pin 26. In the present view, blade cam 50 is in contact with lock
tongue 48 of blade lock 42. When folding knife 10 reaches this
stage of articulation, blade lock 42 begins to provide frictional
resistance to the articulation of blade 12.
FIG. 6 illustrates folding knife 10 when folding knife 10 reaches
its second equilibrium stage during articulation of blade 12.
Spring arm 20 continues to supply an opening force on blade 12, but
the opening force supplied at this stage or articulation is less
than the opening force supplied in the previous stage. The opening
force is less than the previous stage because a greater portion of
the spring force is exerted in the direction of contact-pivot line
36. Likewise, a smaller portion of the spring force is exerted in a
direction perpendicular to contact-pivot line 36.
The second equilibrium stage is achieved when the force exerted by
lock tongue 48 on blade cam 50 matches the opening force supplied
by spring arm 20. As shown in FIG. 6, the increasing radius of
blade cam 50 pushes lock tongue 48 out of the bottom of liner 14.
This pushing force is illustrated by the arrow beneath lock tongue
48 in FIG. 6. Blade lock 42 is a lever and pivots around pivot 44.
When blade lock 42 rotates around pivot 44 lock base 46 makes
contact with toe 60 of arm base 30. Toe 60 supplies a force that
acts to resist the rotation of blade lock 42 around pivot 44.
Accordingly, the second equilibrium stage is achieved when the
force supplied to toe 60 of the spring is sufficient to counteract
the opening force supplied by spring arm 20.
Folding knife 10 is shown in its completely open stage in FIG. 7.
The reader will note that to articulate folding knife from its
second equilibrium stage to the present stage, the user must
provide additional opening force on the knife. This can be
accomplished in a couple of ways. First, the user may simply grab
the non cutting edge side of blade 12 and rotate blade 12 around
pivot pin 26 until it locks. Alternatively, the user may press lock
base 46 against toe 60, so that the opening force supplied by
spring arm 20 causes blade 12 to rotate around pivot pin 26 until
it locks. The blade locks in place as lock tongue 48 inserts into
blade notch 52 at the base of blade 12. Because the user must
supply the opening force to completely open the blade, the proposed
invention cannot be classified as a switchblade and avoids the
prohibitions and restrictions placed on such knives.
The preceding description contains significant detail regarding the
novel aspects of the present invention. It should not be construed,
however, as limiting the scope of the invention but rather as
providing illustrations of the preferred embodiments of the
invention. As an example, it is not necessary that the same spring
be used to supply spring force to guide pin 28 and blade lock 42.
Instead, a separate spring may also be provided to engage the base
of blade lock 42. Such variations would not alter the function of
the invention. Thus, the scope of the invention should be fixed by
the following claims, rather than by the examples given.
* * * * *